1. Field of the Invention
The present invention relates generally to medical methods and devices. More particularly, the present invention relates to methods and apparatus for laterally decompressing spinal nerves to relieve lower back and/or leg pain.
Spinal diseases are among the most frequent causes of discomfort and disability in patients in the United States and elsewhere around the world, frequently requiring surgical intervention for relief. Back and/or leg pain resulting from spinal disease is frequently the result of spinal stenosis which result from narrowing of one or more nerve passages in the spine, most often in the upper (cervical) spine or the lower (lumbar) spine. Such narrowing can apply pressure to the spinal nerves which can cause a variety of symptoms, including pain, cramping, numbness in the legs, back, neck, shoulders, or arms. In some cases, there will be a loss of sensation and/or motor function in the arms or legs and in other cases, bladder or bowel function can be adversely impacted.
Of particular interest to the present invention, pain in the lower back and legs often arises from spinal stenosis in the lumbar spine when the spinal canal or foramen (the area where nerve roots exit the spinal canal) is stenosed applying pressure to a spinal nerve, such as a transversing nerve, an exiting nerve, or nerves of the cauda equina.
While mild symptoms of spinal stenosis in the lumbar region and elsewhere can frequently be treated with pain relievers, physical therapy, braces, or other non-surgical approaches, more severe cases frequently require surgical intervention. Conventional surgical interventions include laminotomy and medial facetectomy, where small portions of the lamina and superior articular process are removed to relieve pressure on the traversing nerve roots. Foraminotomy is an alternative procedure which removes a small portion of the superior articular process and lamina to enlarge the space surrounding the exiting nerve roots.
While often effective, each of these treatment protocols generally requires surgical access to the spine which in turn requires cutting and displacing major muscles and ligaments surrounding the spine. Such procedures are necessarily performed under a general anesthesia and may require hospital stays. Recovery times vary from weeks to months and extensive rehabilitation is usually necessary.
For these reasons, it would be desirable to provide methods and tools for performing less invasive interventions to treat spinal stenosis. It would be particularly desirable if such protocols could utilize relatively small access cannuli and could be performed under external and/or endoscopic visualization. At least some of these objectives will be met by the inventions described hereinbelow.
2. Description of the Background Art
US2009/0036936 and US2008/0221383 describe minimally invasive procedures for treating spinal stenosis by percutaneously accessing the epidural space. US 2005/197661 describes a rotating bone burr and use of the bone burr in performing a laminectomy. The tool is introduced through an incision in the back. Other patents and published applications of interest include U.S. Pat. Nos. 6,740,090; 6,258,093; 6,174,313; 5,755,718; US 2008/071282; US 2006/217728; and US 2006/004369.